Disc players heretofore known include those wherein a tray box is removably mounted on the main chassis of the player main body. The tray box has accommodated therein a plurality discs as individually placed on trays arranged in a multiplicity of stages. The desired one of the discs is horizontally withdrawn from the tray box along with the tray and set in the signal reproduction unit within the player main body. At this time, the reproduction unit including a turntable and a pickup is raised to the level of the withdrawn disc and reproduces the signals at this level.
FIG. 21 shows a drive mechanism proposed for raising the reproduction unit to a specified level (Unexamined Japanese Patent Publication SHO No. 61-261851).
This mechanism comprises a lift chassis 5 having the reproduction unit (not shown). The lift chassis 5 is movable upward and downward stepwise, whereby the reproduction unit is positioned as opposed to the desired disc D within a tray box 27. The lift chassis 5 is driven by drive slides 109 formed with steplike slanting grooves 110, 110.
The lift chassis 5 is accommodated in a main chassis 1 with vertical grooves 112, 112 formed in its side plates. Each drive slide 109 is disposed along the side plate, and the slanting groove 110 includes horizontal portions and slanting portions. Each of pins 6, 6 projecting from the side plate of the lift chassis 5 is inserted through the vertical groove 112 and the slanting groove 110 at the intersection thereof. Accordingly, when the drive slides 109 are moved rightward or leftward by driving a motor 111, the pins 6 are pushed by the slanting grooved portions 110 of the drive slides 109, whereby the lift chassis 5 is moved stepwise upward or downward.
The slanting groove 110 comprises the horizontal and slanting portions and has a zigzag shape to render the lift chassis 5 properly positionable at rest at different levels. The above mechanism therefore has the problem that when the pin 6 shifts from the horizontal portion to the slanting portion with the movement of the drive slide 109, the motor 111 is subjected to an abruptly increased load, failing to smoothly move the lift chassis 5. Furthermore, the horizontal portions, included in the slanting groove 110 and not contributing to the ascent or descent of the lift chassis 5, give an increased horizontal dimension to the drive slide 109 and add to the stroke length of the drive slide 109. The mechanism therefore has the problem of making the disc player large-sized.